These types of joint-sealing tapes usually consist of polyethylene or polyurethane foam, and are used, for example, in the construction industry, where the joints between window frames or door frames and the masonry must be sealed. The foam materials have a cellular structure made up of webs with pores between them. The spectrum of flexible foams extends from closed-cell foams, which allow virtually no air to pass through, to open-cell foams, which have relatively high permeability to air. At least the open-cell foams are usually saturated with an impregnate to achieve the desired sealing properties. Such impregnates also lead to a delayed recovery of the foam after its compression, because the impregnates usually contain adhesive substances, which settle on the cell webs of the foam structure and adhere there. Use is often made of the delayed recovery effect when joints are to be sealed, in that the foam is first compressed and inserted into the joint to be sealed, whereupon the foam partially reexpands to assume its functional state and seals the joint. The impregnate can also be used to obtain other positive properties such as fire safety properties or protection against UV radiation.
To obtain joint-sealing tapes with extremely high sealing values, it is also desirable to impregnate foams with relatively closed cells, as described in EP 1 600 571 A1. Nevertheless, the complete saturation of relatively closed-cell foams is very difficult and is also subject to limitations with respect to the choice of impregnation agent.
Saturation with high-viscosity impregnates is difficult to achieve even in the case of open-cell foams. And it is been almost completely impossible so far to impregnate completely closed-cell foams.
It is therefore an object of the present invention to create a joint-sealing tape of flexible foam capable of recovery after compression which can be impregnated very easily and which also achieves extremely high sealing values.